In general, a piece of furniture, such as a desk or closet, or a home appliance, such as a refrigerator, a washing machine or a microwave oven, is provided with a receptacle which is pushed in and pulled out in a state in which an object is contained therein. A body of the furniture or home appliance has an accommodating space, and the receptacle having an inner space in which the object is contained is slidably coupled via a sliding device, which is disposed on both sides thereof, such that it can slide into and out of the accommodating space.
A typical sliding device is disposed between the body and the receptacle, in which a rail fixed to the body and a rail which moves along with the receptacle are disposed such that they overlap each other. Rolling means such as balls or rollers are disposed between the overlapping rails such that the fixed rail and the movable rail come into rolling-contact with each other.
In this sliding device, the rolling means is disposed between the rail of the receptacle and the rail of the body such that the receptacle moves via rolling when it is pulled out and pushed in. Accordingly, the receptacle can be smoothly opened and closed when it is pulled out and pushed in. In addition, the rails have a double structure that includes the rail fixed to the body and the rail fixed to the receptacle. In order to increase the length to which the receptacle is pushed out, a triple rail structure in which an intermediate rail is disposed between the fixed rail and the movable rail can be provided. Since the sliding structure is identical irrespective of the double or triple rail structure, it is apparent to a person having ordinary skill in the art that these structures belong to the same category.
The rolling means disposed between the overlapping rails in the sliding device includes a retainer which allows a plurality of balls or rollers to stay in the same interval in the state in which they are disposed at positions where they come into rolling-contact with each other.
A typical retainer is disposed between the fixed rail and the movable rail, and has a configuration that minimizes interference during movement. A plurality of rolling members, such as balls and rollers, are inserted at positions where the fixed rail and the movable rail overlap each other, and stay at predetermined intervals.
Specifically, in the sliding device, the rail fixed to the body has the shape of a letter “C,” and the rail which moves along with the receptacle has the same shape such that it can be inserted into the open portion. Accordingly, the retainer which is inserted into the fixed rail and the movable rail has the same shape so as not to interfere with either of them.
In addition, the rolling members fitted to the retainer, which is inserted at a position where the movable rail overlaps the fixed rail at protruding surfaces which face each other, can come into rolling-contact with both of the fixed rail and the movable rail.
In addition, the retainer disposed between the fixed rail and the movable rail has the function of supporting the rolling members and limiting the length to which the movable rail, which slides on the fixed rail in the overlapping fashion, is pulled out in order to prevent the movable rail from be dislodged to the outside. Specifically, the retainer moves in rolling-contact between the fixed rail and the movable rail, and has a protrusion at one end in the pulling-out direction, the protrusion preventing the retainer from being dislodged. The movable rail also has a protrusion which is held by the retainer in order to prevent dislodgment. In other words, when the receptacle is pulled out, one side of the retainer in the pulling-out direction is held by the protrusion on the fixed rail, thereby preventing the retainer and the movable rail from being dislodged to the outside. In addition, the other side of the retainer in the closing direction is held by the protrusion on the movable rail, thereby limiting the length to which the receptacle slides when it is pushed in.
Such a retainer has the following problems: When the receptacle is pulled out, both sides of the receptacle are held by the protrusions on the rails. An impact is thereby transferred to the receptacle, thereby generating noise. In addition, damage may occur due to repeated impact.
In addition, a typical retainer is strong enough to withstand an impact transferred thereto, since it is made of the same metal material as the rails. However, when the rail moves, the rolling members which are disposed for rolling movement are rubbed against the metal-made retainer, thereby creating noise. This may also damage the rolling members.
In addition, the retainer made of the metal material must be formed such that it has the shape of a letter “C” corresponding to the shape of the rails and that the rolling members can be inserted into opposing surfaces so that they can roll. This makes machining difficult, thereby increasing the machining cost. When the metal material is exposed to moisture, corrosion occurs, and frictional sound is produced thereby. During a pulling out action, the retainer collides against with the rails made of the same metal material, thereby creating noise.
Accordingly, recently, a retainer has been made of a synthetic resin material in order to reduce noise due to friction against the rolling members and minimize the damage of the rolling members.
However, the retainer of the related art is less strong than the metal material in terms of withstanding an impact that occurs during a pulling out action. When the receptacle is repeatedly pulled out, the retainer may be easily broken by impact that is transferred thereto, which is problematic.
In addition, in the retainer of the related art, when the receptacle is pulled out, both sides of the retainer collide against the protrusions on the rails so that the rail is prevented from being dislodged and the length to which the receptacle is pulled out is changed. At this time, noise is produced to due to impact, which is problematic.
Furthermore, when the receptacle is pulled out, an impact is created as the retainer of the related art collides against the rail. The impact is concentrated at the contact surface, which may be broken when an impact repeatedly occurs due to continuous pulling-out actions, which is problematic.